why is it too hard to cover them? are they in your front yard?
besides... you'll only need to have them covered at night.. who's looking on your private property at night? i dont think 40 degree weather will go over well with them.... dont plants like 70-80 degree weather? maybe even 60-80... but 40's just too cold... your buds might turn purple, which isnt necessarily bad... but its not natural for the strain you're growing.. the cold weather makes them basically go into defense mode... u know how when humans are cold they kinda tense up and shiver, and maybe try to compact themselves, like hold your arms and legs or something to keep all the heat in one area... plants do pretty much the same thing... it might not make ur bud bad... but if i were you i wouldnt wana risk it... i DEFINITELY wouldnt want to risk them dying from the cold or even hybernating, i have no idea how hybernation would affect a cannabis plant. as for the seeds... if they have been outside the whole time, theyve been getting about 12 on 12 off of light since the beginning, no? that is a prime factor that causes hermaphrodites... for the seedling and veg. stage they should be under 18:6 or 24:0... next year try growing indoors if you can... it'll make things a lot more controlable, not to mention the quality will most likely be wayyyy better. a typical closet works for a few to several plants.... it gets kind of expensive but i think its worth it... i live in cali, so i can pretty much buy weed any time i want to... idk how it is there but if good quality shit is scarce.... id say its even more worth it to grow inside. im growing inside right now, i just started 3 clones a few days ago, theyre looking nice. your plants look really nice for this being your first or second try..


but yeah as for the weather.... do your best to cover them at night... if you cant, hmmm idk maybe get an outdoors heater and stick a fan behind it... dont leave it too close to the plants cuz u dont wana burn them... but yeah idk im just being creative ... somebody with more experience might say thats a horrible idea.. probably wana check with someone else b4 u give that a go.. id say get a big cardboard box or a black tarp n put em under there for the night time.. if not the whole night... just like 11pm or midnight till just before sunrise... thats when its coldest, no?